The present invention relates to a container with at least one wall element which is made of one or more sheet-like segments having at least one edge enclosed by a protective covering which covers the inner surface and the outer surface of the area bordering the edge. The area has such a reduced thickness that the segment including the protective covering has at least an almost constant thickness.
German published patent application 3023835 describes a container which is made up of a plurality of wall elements. Each wall element comprises a paper carrier layer covered by at least one protective layer which is directed towards the inside of the container after assembly thereof. During production of the container, a segment is formed into an essentially conical body portion. An end area of the segment with an edge projects thereby into the inside of the container.
The edge projecting into the inside of the container is surrounded by a protective covering. The protective layer of the segment serves as a protective covering, which is folded over at an angle of 180.degree. in the area of the edge so that the edge itself, and the area of the segment joined thereto are surrounded by the protective covering.
First, for the production and application of the known protective covering, the carrier layer of the segment in the end area comprising the edge is skived, so that the segment there possesses essentially only half material size. A longitudinal groove is then formed at the bisecting line of the skived area and an adhesive is applied to the skived area. Finally, the skived area is folded over at an angle of 180.degree. along the longitudinal groove and adhered together. This process makes a protective covering in the area of the edge, and the covering is formed by the folded protective layer of the segment to cover the edge itself as well as the two sides of the segment resting on each other and joined to the edge.
Due to the paring down of the material at the longitudinal end to half its thickness, and the subsequent folding together of the end strip, a thickness is maintained in the area of the edge which corresponds overall at least approximately to the thickness of the segment. The segment, including the protective covering, has an overall, at least approximately, constant thickness. The purpose of the skiving of the material at the end area of the segment is to avoid cracks forming during folding, which cracks can occur in the case of full-strength material.
An object of the present invention is to provide in a container an edge protection which is simple and cost-effective to produce without having to increase a segment thickness.
This object has been achieved in accordance with the present invention by compressing the area to be covered by the protective covering.
The container and process therefor according to the present invention has the advantage that the reduction of the thickness of the segment in the area to be covered by the protective covering can be carried out in a particularly simple and cost-effective way. After application of the protective covering onto the area with a reduced thickness, the segment that is used for producing the container has an overall, at least approximately constant, thickness.
The approximately constant thickness makes possible a simplified production of the container. Segments of constant thickness are particularly good for stacking in piles to feed to container manufacturing machines. Also a plurality of segments can be put together to form a cardboard tape which can be presented in rolled-up form to a container manufacturing machine.
The present invention can be applied usefully to all containers where it is to be avoided that a medium, in particular the liquid contents, leaks into the wall elements of the container. In the edge area, the surface of the segment which is to be made into a wall element of the container is frequently broken open, particularly when the edge is made by cutting or punching. By applying the protective covering, the same or a similar protection can be made in the edge area as exist in the other areas of the container regardless of the outer shape of the container.
Another advantageous aspect of the present invention involves a segment which comprises a carrier layer and a protective layer. The thickness in the edge area is reduced in that the protective layer and/or the carrier layer is compressed. The protective covering can itself be compressed advantageously in the area of the segment to be covered.
In one advantageous embodiment of the present invention the protective covering is made in one with the protective layer of the segment.
Moreover, the present invention can be applied to all edges of a container to be covered with a protective covering.
In an advantageous embodiment of the present invention, a segment is made into a wall and forms a side body element of the container. Consequently, a section of the segment is so arranged that it overlaps the inner surface of the wall and is fastened thereagainst to project into the inside of the side body element. The end of the section is formed by an edge which is covered with a protective covering.
According to another advantageous aspect of the present invention, the edge to be covered is provided at an opening which is set in a container wall. This opening can be advantageously covered by a pull tab, whereby the area of the segment which can be covered by the pull tab also has a reduced thickness. The segment is then essentially of constant thickness in the area covered by the protective covering as well as in the area covered by the pull tab.
Compression of the segment is advantageously carried out by applying mechanical pressure to the area to be compressed.